Fix stack overflow when inspecting circular JSX elements

[robobun]

What does this PR do?

Fixes a stack overflow crash in Bun.inspect / console.log when formatting a React element whose props or children form a cycle back to the element itself.

const el = {
  $$typeof: Symbol.for("react.element"),
  type: "div",
};
el.props = el;
Bun.inspect(el); // segfault (stack overflow)

The JSX formatter was not included in canHaveCircularReferences(), so the visited-map check never ran for .JSX tags and the formatter recursed until the stack blew out.

Also fixes a null-unwrap panic when props is set to a non-object value — the formatter assumed props was always an object and did props.getObject().?. Now it skips prop iteration when props is not an object.

How did you verify your code works?

Added regression tests to test/js/bun/util/inspect.test.js covering circular props, circular children, and non-object props.

Found by Fuzzilli (fingerprint 380dfde18006ab21).

[robobun]

^{Updated 11:11 AM PT - May 13th, 2026}

❌ @robobun, your commit 17c406c has 1 failures in Build #54053 (All Failures):

• scripts/build/ci.ts - build failed on 🐧 x64-android - build-zig
• scripts/build/ci.ts - build failed on 🐧 aarch64-android - build-zig
• scripts/build/ci.ts - build failed on :freebsd: x64 - build-zig
• scripts/build/ci.ts - build failed on :freebsd: aarch64 - build-zig
• scripts/build/ci.ts - build failed on 🐧 x64-musl-baseline - build-zig
• scripts/build/ci.ts - build failed on 🍎 aarch64 - build-zig
• scripts/build/ci.ts - build failed on 🐧 x64-baseline - build-zig
• scripts/build/ci.ts - build failed on 🐧 x64 - build-zig
• scripts/build/ci.ts - build failed on 🐧 aarch64-musl - build-zig
• scripts/build/ci.ts - build failed on 🐧 aarch64 - build-zig
• scripts/build/ci.ts - build failed on 🍎 x64 - build-zig
• scripts/build/ci.ts - build failed on 🐧 x64-musl - build-zig

---

🧪   To try this PR locally:

bunx bun-pr 30629

That installs a local version of the PR into your bun-30629 executable, so you can run:

bun-30629 --bun

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between b9c757b and e1f3bbe.

📒 Files selected for processing (2)

• src/jsc/ConsoleObject.zig
• test/js/bun/util/inspect.test.js

---

Walkthrough

JSX console formatting gains circular reference detection and improved robustness: the formatter now recognizes .JSX values as circular-reference–eligible, and JSX props field handling safely obtains an object without force-unwrapping, enabling graceful handling of non-object prop values. Tests validate circular reference rendering and non-object prop edge cases.

Changes

JSX Circular Reference and Props Handling

Layer / File(s)	Summary
JSX circular eligibility and props safety src/jsc/ConsoleObject.zig	canHaveCircularReferences now includes .JSX values; JSX props formatting replaces force-unwrap with a checked getObject() call, breaking early when props is non-object.
JSX formatting test cases test/js/bun/util/inspect.test.js	Three tests verify circular references in JSX props and props.children render [Circular] markers, and that non-object props renders a self-closing tag.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: fixing stack overflow when inspecting circular JSX elements, which matches the core issue addressed in the changeset.
Description check	✅ Passed	The description covers both required template sections with detailed explanations: it explains what the PR does (fixes stack overflow and null-unwrap panic) and how it was verified (regression tests added, found by Fuzzilli).
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[github-actions]

This PR may be a duplicate of:

1. Fix crash when inspecting JSX elements with circular or non-object props #30630 - Same fix: adds .JSX to canHaveCircularReferences() and fixes non-object props null-unwrap in ConsoleObject.zig
2. Fix stack overflow in Bun.inspect() on circular JSX elements #29709 - Same fix: adds .JSX to canHaveCircularReferences() and safely handles non-object props via orelse break :props
3. Fix stack overflow in Bun.inspect for circular JSX elements #30126 - Partial overlap: adds .JSX to canHaveCircularReferences() to fix the same circular JSX stack overflow (lacks non-object props fix)

🤖 Generated with Claude Code

[robobun]

Duplicate of #29709, which has the same fix plus the equivalent change in pretty_format.zig.